Conductive polishing article for electrochemical mechanical polishing

ABSTRACT

An article of manufacture and apparatus are provided for planarizing a substrate surface. In one aspect, an article of manufacture is provided for polishing a substrate including polishing article comprising a body having at least a partially conductive surface adapted to polish the substrate. A plurality of perforations may be formed in the polishing article for flow of material therethrough. An electrode is also exposed to the polishing surface by at least a portion of the plurality of perforations. The article of manufacture may also include a polishing surface having a plurality of grooves, wherein a portion of the plurality of grooves intersect with a portion of the plurality of perforations.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/393,220, filed Mar. 30, 2006, now U.S. Pat. No. 7,137,879 which is acontinuation of U.S. patent application Ser. No. 10/033,732, filed onDec. 27, 2001 and issued as U.S. Pat. No. 7,066,800 on Jun. 27, 2006,which application claims benefit of U.S. Provisional Patent ApplicationSer. No. 60/286,107, filed Apr. 24, 2001, and U.S. Provisional PatentApplication Ser. No. 60/326,263, filed Oct. 1, 2001, and eachapplication is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an article of manufacture and apparatusfor planarizing a substrate surface.

2. Background of the Related Art

Sub-quarter micron multi-level metallization is one of the keytechnologies for the next generation of ultra large-scale integration(ULSI). The multilevel interconnects that lie at the heart of thistechnology require planarization of interconnect features formed in highaspect ratio apertures, including contacts, vias, lines and otherfeatures. Reliable formation of these interconnect features is veryimportant to the success of ULSI and to the continued effort to increasecircuit density and quality on individual substrates and die.

In the fabrication of integrated circuits and other electronic devices,multiple layers of conducting, semiconducting, and dielectric materialsare deposited on or removed from a surface of a substrate. Thin layersof conducting, semiconducting, and dielectric materials may be depositedby a number of deposition techniques. Common deposition techniques inmodern processing include physical vapor deposition (PVD), also known assputtering, chemical vapor deposition (CVD), plasma-enhanced chemicalvapor deposition (PECVD), and electrochemical plating (ECP).

As layers of materials are sequentially deposited and removed, theuppermost surface of the substrate may become non-planar across itssurface and require planarization. Planarizing a surface, or “polishing”a surface, is a process where material is removed from the surface ofthe substrate to form a generally even, planar surface. Planarization isuseful in removing undesired surface topography and surface defects,such as rough surfaces, agglomerated materials, crystal lattice damage,scratches, and contaminated layers or materials. Planarization is alsouseful in forming features on a substrate by removing excess depositedmaterial used to fill the features and to provide an even surface forsubsequent levels of metallization and processing.

Chemical mechanical planarization, or chemical mechanical polishing(CMP), is a common technique used to planarize substrates. CMP utilizesa chemical composition, typically a slurry or other fluid medium, forselective removal of material from substrates. In conventional CMPtechniques, a substrate carrier or polishing head is mounted on acarrier assembly and positioned in contact with a polishing pad in a CMPapparatus. The carrier assembly provides a controllable pressure to thesubstrate urging the substrate against the polishing pad. The pad ismoved relative to the substrate by an external driving force. The CMPapparatus effects polishing or rubbing movement between the surface ofthe substrate and the polishing pad while dispersing a polishingcomposition to effect chemical activity and/or mechanical activity andconsequential removal of material from the surface of the substrate.

One material increasingly utilized in integrated circuit fabrication iscopper due to its desirable electrical properties. However, copper hasits own special fabrication problems. For example, copper is difficultto pattern and etch and new processes and techniques, such as damasceneor dual damascene processes, are being used to form copper substratefeatures. In damascene processes, a feature is defined in a dielectricmaterial and subsequently filled with copper. Dielectric materials withlow dielectric constants, i.e., less than about 3, are being used in themanufacture of copper damascenes. Barrier layer materials are depositedconformally on the surfaces of the features formed in the dielectriclayer prior to deposition of copper material. Copper material is thendeposited over the barrier layer and the surrounding field. However,copper fill of the features usually results in excess copper material,or overburden, on the substrate surface that must be removed to form acopper filled feature in the dielectric material and prepare thesubstrate surface for subsequent processing.

One challenge that is presented in polishing copper materials is thatthe interface between the conductive material and the barrier layer isgenerally non-planar and residual copper material is retained inirregularities formed by the non-planar interface. Further, theconductive material and the barrier materials are often removed from thesubstrate surface at different rates, both of which can result in excessconductive material being retained as residues on the substrate surface.Additionally, the substrate surface may have different surfacetopography, depending on the density or size of features formed therein.Copper material is removed at different removal rates along thedifferent surface topography of the substrate surface, which makeseffective removal of copper material from the substrate surface andfinal planarity of the substrate surface difficult to achieve.

One solution to remove all of the desired copper material from thesubstrate surface is to overpolish the substrate surface. However,overpolishing of some materials can result in the formation oftopographical defects, such as concavities or depressions in features,referred to as dishing, or excessive removal of dielectric material,referred to as erosion. The topographical defects from dishing anderosion can further lead to non-uniform removal of additional materials,such as barrier layer materials disposed thereunder, and produce asubstrate surface having a less than desirable polishing quality.

Another problem with the polishing of copper surfaces arises from theuse of low dielectric constant (low k) dielectric materials to formcopper damascenes in the substrate surface. Low k dielectric materials,such as carbon doped silicon oxides, may deform or fracture underconventional polishing pressures (i.e., about 6 psi), called downforce,which can detrimentally affect substrate polish quality anddetrimentally affect device formation. For example, relative rotationalmovement between the substrate and a polishing pad can induce a shearforce along the substrate surface and deform the low k material to formtopographical defects, which can detrimentally affect subsequentpolishing.

One solution for polishing copper in low dielectric materials withreduced or minimal defects formed thereon is by polishing copper byelectrochemical mechanical polishing (ECMP) techniques. ECMP techniquesremove conductive material from a substrate surface by electrochemicaldissolution while concurrently polishing the substrate with reducedmechanical abrasion compared to conventional CMP processes. Theelectrochemical dissolution is performed by applying a bias between acathode and substrate surface to remove conductive materials from asubstrate surface into a surrounding electrolyte. In one embodiment ofan ECMP system, the bias is applied by a ring of conductive contacts inelectrical communication with the substrate surface in a substratesupport device, such as a substrate carrier head. However, the contactring has been observed to exhibit non-uniform distribution of currentover the substrate surface, which results in non-uniform dissolution.Mechanical abrasion is performed by positioning the substrate in contactwith conventional polishing pads and providing relative motiontherebetween. However, conventional polishing pads often limitelectrolyte flow to the surface of the substrate. Additionally, thepolishing pad may be composed of insulative materials that may interferewith the application of bias to the substrate surface and result innon-uniform or variable dissolution of material from the substratesurface.

As a result, there is a need for an improved polishing article for theremoval of conductive material on a substrate surface.

SUMMARY OF THE INVENTION

Aspects of the invention generally provide an article of manufacture andan apparatus for planarizing a layer on a substrate usingelectrochemical deposition techniques, electrochemical dissolutiontechniques, polishing techniques, and combinations thereof. In oneembodiment, an article of manufacture for polishing a substrate isdescribed. The article of manufacture includes, a conductive materiallayer, a polishing material having a partially conductive polishingsurface disposed on the conductive material layer, the partiallyconductive polishing surface adapted to contact the substrate, aplurality of perforations formed in the conductive material layer andthe polishing material, and a plurality of grooves disposed in thepolishing material.

In another embodiment, an article of manufacture for polishing asubstrate is described. The article of manufacture includes, aperforated dielectric support layer, a perforated conductive layerdisposed on the perforated dielectric support layer, and a polishingmaterial disposed on the conductive material layer, the polishingmaterial having a partially conductive polishing surface adapted tocontact the substrate and having a plurality of perforations and aplurality of grooves formed therein, wherein the conductive materiallayer comprises one or more conductive contacts adapted to couple to apower source.

In another embodiment, an article of manufacture for polishing asubstrate is described. The article of manufacture includes, aconductive material layer, a polishing material having a partiallyconductive polishing surface disposed on the conductive material layer,the partially conductive polishing surface adapted to contact thesubstrate, an electrode disposed below the conductive material layer, aplurality of perforations formed in the conductive material layer andthe polishing material, and a plurality of grooves disposed in thepolishing material, wherein the electrode is exposed to the pluralityconductive polishing surface by the plurality of perforations formed inthe conductive material layer and the polishing material.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited aspects of the inventionare attained and can be understood in detail, a more particulardescription of the invention, briefly summarized above, may be had byreference to the embodiments thereof which are illustrated in theappended drawings.

It is to be noted, however, that the appended drawings illustrate onlytypical embodiments of this invention and, therefore, are not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments.

FIG. 1 is a plan view of one embodiment of a processing apparatus of theinvention;

FIG. 2 is a sectional view of one embodiment of an ECMP station;

FIG. 3 is a side schematic view of one embodiment of the polishingarticle;

FIG. 4 is a side schematic view of another embodiment of the polishingarticle;

FIGS. 5A-5B are side schematic views of another embodiment of thepolishing article;

FIG. 6 is a side schematic view of another embodiment of the polishingarticle;

FIG. 7 is a top plan view of one embodiment of a grooved polishingarticle;

FIG. 8 is a top plan view of another embodiment of a grooved polishingarticle;

FIG. 9 is a top plan view of another embodiment of a grooved polishingarticle;

FIG. 10A is perspective view of one embodiment of a polishing articlehaving a conductive element;

FIG. 10B is partial perspective view of another embodiment of apolishing article having a conductive element;

FIG. 10C is partial perspective view of another embodiment of apolishing article having a conductive element;

FIG. 10D is detailed view of the polishing article of FIG. 10C;

FIG. 11A is a partial sectional view of another embodiment of aconductive element;

FIG. 11B is a partial sectional view of another embodiment of aconductive element;

FIG. 12A is a partial sectional view of another embodiment of aconductive element;

FIG. 12B is a partial sectional view of another embodiment of aconductive element;

FIG. 13 is perspective view of another embodiment of a polishing articlehaving a conductive element;

FIG. 14A is a partial perspective view of another embodiment of apolishing article;

FIG. 14B is a perspective view of another embodiment of a polishingarticle;

FIG. 14C is a partial perspective view of another embodiment of apolishing article;

FIG. 14D shows another embodiment of a polishing article havingconductive elements comprising loops secured to the polishing article;and

FIGS. 15A-D are schematic top and side views of one embodiment of ainlet power pad mounted on the polishing article described herein.

To facilitate understanding, identical reference numerals have beenused, wherever possible, to designate identical elements that are commonto the figures.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The words and phrases used herein should be given their ordinary andcustomary meaning in the art by one skilled in the art unless otherwisefurther defined. Chemical-mechanical polishing should be broadlyconstrued and includes, but is not limited to, abrading a substratesurface by chemical activity, mechanical activity, or a combination ofboth chemical and mechanical activity. Electropolishing should bebroadly construed and includes, but is not limited to, planarizing asubstrate by the application of electrochemical activity, such as byanodic dissolution. Electrochemical mechanical polishing (ECMP) shouldbe broadly construed and includes, but is not limited to, planarizing asubstrate by the application of electrochemical activity, mechanicalactivity, or a combination of both electrochemical and mechanicalactivity to remove material from a substrate surface. Electrochemicalmechanical plating process (ECMPP) should be broadly construed andincludes, but is not limited to, electrochemically depositing materialon a substrate and concurrently planarizing the deposited material bythe application of electrochemical activity, mechanical activity, or acombination of both electrochemical and mechanical activity.

Anodic dissolution should be broadly construed and includes, but is notlimited to, the application of an anodic bias to a substrate directly orindirectly which results in the removal of conductive material from asubstrate surface and into a surrounding electrolyte solution.Perforation should be broadly construed and includes, but is not limitedto, an aperture, hole, opening, channel, or passage formed partially orcompletely through an object, such as a polishing article.

FIG. 1 depicts a processing apparatus 100 having at least one stationsuitable for electrochemical deposition and chemical mechanicalpolishing, such as electrochemical mechanical polishing (ECMP) station102 and at least one conventional polishing or buffing station 106disposed on a single platform or tool. One polishing tool that may beadapted to benefit from the invention is a MIRRA® chemical mechanicalpolisher available from Applied Materials, Inc. located in Santa Clara,Calif.

The exemplary apparatus 100 generally includes a base 108 that supportsone or more ECMP stations 102, one or more polishing stations 106, atransfer station 110 and a carousel 112. The transfer station 110generally facilitates transfer of substrates 114 to and from theapparatus 100 via a loading robot 116. The loading robot 116 typicallytransfers substrates 114 between the transfer station 110 and a factoryinterface 120 that may include a cleaning module 122, a metrology device104 and one or more substrate storage cassettes 118. One example of ametrology device 104 is a NovaScan™ Integrated Thickness Monitoringsystem, available from Nova Measuring Instruments, Inc., located inPhoenix, Ariz.

Alternatively, the loading robot 116 (or factory interface 120) maytransfer substrates to one or more other processing tools (not shown)such as a chemical vapor deposition tool, physical vapor depositiontool, etch tool and the like.

In one embodiment, the transfer station 110 comprises at least an inputbuffer station 124, an output buffer station 126, a transfer robot 132,and a load cup assembly 128. The loading robot 116 places the substrate114 onto the input buffer station 124. The transfer robot 132 has twogripper assemblies, each having pneumatic gripper fingers that hold thesubstrate 114 by the substrate's edge. The transfer robot 132 lifts thesubstrate 114 from the input buffer station 124 and rotates the gripperand substrate 114 to position the substrate 114 over the load cupassembly 128, then places the substrate 114 down onto the load cupassembly 128.

The carousel 112 generally supports a plurality of polishing heads 130,each of which retains one substrate 114 during processing. The carousel112 transfers the polishing heads 130 between the transfer station 110,the one or more ECMP stations 102 and the one or more polishing stations106. One carousel 112 that may be adapted to benefit from the inventionis generally described in U.S. Pat. No. 5,804,507, issued Sep. 8, 1998to Tolles et al., which is hereby incorporated by reference to theextent it is not inconsistent with the claims and disclosure herein.

Generally, the carousel 112 is centrally disposed on the base 108. Thecarousel 112 typically includes a plurality of arms 138. Each arm 138generally supports one of the polishing heads 130. One of the arms 138depicted in FIG. 1 is not shown so that the transfer station 110 may beseen. The carousel 112 is indexable such that the polishing head 130 maybe moved between the stations 102, 106 and the transfer station 110 in asequence defined by the user.

Generally the polishing head 130 retains the substrate 114 while thesubstrate 114 is disposed in the ECMP station 102 or polishing station106. The arrangement of the ECMP stations 106 and polishing stations 102on the apparatus 100 allow for the substrate 114 to be sequentiallyplated or polished by moving the substrate between stations while beingretained in the same polishing head 130. One polishing head that may beadapted to be used in the invention is a TITAN HEAD™ substrate carrier,manufactured by Applied Materials, Inc., located in Santa Clara, Calif.

Examples of embodiments of polishing heads 130 that may be used with thepolishing apparatus 100 described herein are described in U.S. Pat. No.6,024,630, issued Feb. 25, 2000 to Shendon, et al., which is herebyincorporated by reference to the extent it is not inconsistent with theclaims and disclosure herein.

To facilitate control of the polishing apparatus 100 and processesperformed thereon, a controller 140 comprising a central processing unit(CPU) 142, memory 144, and support circuits 146, is connected to thepolishing apparatus 100. The CPU 142 may be one of any form of computerprocessor that can be used in an industrial setting for controllingvarious drives and pressures. The memory 144 is connected to the CPU142. The memory 144, or computer-readable medium, may be one or more ofreadily available memory such as random access memory (RAM), read onlymemory (ROM), floppy disk, hard disk, or any other form of digitalstorage, local or remote. The support circuits 146 are connected to theCPU 142 for supporting the processor in a conventional manner. Thesecircuits include cache, power supplies, clock circuits, input/outputcircuitry, subsystems, and the like.

FIG. 2 depicts a sectional view of the polishing head 130 supportedabove an ECMP station 102. The ECMP station 102 generally includes abasin 202, an electrode 204, polishing article 205, a disc 206 and acover 208. In one embodiment, the basin 202 is coupled to the base 108of the polishing apparatus 100. The basin 202 generally defines acontainer or electrolyte cell in which a conductive fluid such as anelectrolyte 220 can be confined. The electrolyte 220 used in processingthe substrate 114 can include metals such as copper, aluminum, tungsten,gold, silver or other materials which can be electrochemically depositedonto or electrochemically removed from the substrate 114.

The basin 202 can be a bowl shaped member made of a plastic such asfluoropolymers, a TEFLON® material, PFA, PE, PES, or other materialsthat are compatible with electroplating and electropolishingchemistries. The basin 202 has a bottom 210 that includes an aperture216 and a drain 214. The aperture 216 is generally disposed in thecenter of the bottom 210 and allows a shaft 212 to pass therethrough. Aseal 218 is disposed between the aperture 216 and the shaft 212 andallows the shaft 212 to rotate while preventing fluids disposed in thebasin 202 from passing through the aperture 216.

The basin 202 typically includes the electrode 204, the disc 206, andthe polishing article 205 disposed therein. Polishing article 205, suchas a polishing pad, is disposed and supported in the basin 202 on thedisc 206.

The electrode 204 is a counter-electrode to the substrate 114 and/orpolishing article 205 contacting a substrate surface. The polishingarticle 205 is at least partially conductive and may act as an electrodein combination with the substrate during electrochemical processes, suchas an electrochemical mechanical plating process (ECMPP), which includeselectrochemical deposition and chemical mechanical polishing, orelectrochemical dissolution. The electrode 204 may be an anode orcathode depending upon the positive bias (anode) or negative bias(cathode) applied between the electrode 204 and polishing article 405.

For example, depositing material from an electrolyte on the substratesurface, the electrode 204 acts as an anode and the substrate surfaceand/or polishing article 205 acts as a cathode. When removing materialfrom a substrate surface, such as by dissolution from an applied bias,the electrode 204 functions as a cathode and the substrate surfaceand/or polishing article 205 may act as an anode for the dissolutionprocess.

The electrode 204 is generally positioned between the disc 206 and thebottom 210 of the basin 202 where it may be immersed in the electrolyte220. The electrode 204 can be a plate-like member, a plate havingmultiple apertures formed therethrough, or a plurality of electrodepieces disposed in a permeable membrane or container. A permeablemembrane (not shown) may be disposed between the disc 206 and theelectrode 204 or electrode 204 and polishing article 205 to filterbubbles, such as hydrogen bubbles, form the wafer surface and to reducedefect formation and stabilize or more uniformly apply current or powertherebetween.

The electrode 204 is comprised of the material to be deposited orremoved, such as copper, aluminum, gold, silver, tungsten and othermaterials which can be electrochemically deposited on the substrate 114.For electrochemical removal processes, such as anodic dissolution, theelectrode 204 may include a non-consumable electrode of a material otherthan the deposited material, such as platinum for copper dissolution.The non-consumable electrode is used in planarization processescombining both electrochemical deposition and removal.

While the following polishing article is described for anelectrochemical-mechanical polishing (ECMP) process, the inventioncontemplates using the conductive polishing article in other fabricationprocesses involving electrochemical activity. Examples of such processesusing electrochemical activity include electrochemical deposition, whichinvolves the polishing article 205 being used to apply a uniform bias toa substrate surface for depositing a conductive material without the useof conventional bias application apparatus, such as edge contacts, andelectrochemical mechanical plating processes (ECMPP) that include acombination of electrochemical deposition and chemical mechanicalpolishing.

The polishing article 205 can be a pad, a web or a belt of material,which is compatible with the fluid environment and the processingspecifications. In the embodiment depicted in FIG. 2, the polishingarticle 205 is circular in form and positioned at an upper end of thebasin 202, supported on its lower surface by the disc 206. The polishingarticle 205 includes at least a partially conductive surface of aconductive material, such as one or more conductive elements, forcontact with the substrate surface during processing. The polishingarticle 205 may be a conductive polishing material or a composite of aconductive polishing material disposed on a conventional polishingmaterial. For example the conductive material may be disposed on a“backing” material disposed between the disc 206 and polishing article205 to tailor the compliance and/or durometer of the polishing article205 during processing.

The basin 202, the cover 208, and the disc 206 may be movably disposedon the base 108. The basin 202, cover 208 and disc 206 may be axiallymoved toward the base 108 to facilitate clearance of the polishing head130 as the carousel 112 indexes the substrate 114 between the ECMP andpolishing stations 102, 106. The disc 206 is disposed in the basin 202and coupled to the shaft 212. The shaft 212 is generally coupled to amotor 224 disposed below the base 108. The motor 224, in response to asignal from the controller 140, rotates the disc 206 at a predeterminedrate.

The disc 206 may be a perforated article support made from a materialcompatible with the electrolyte 220 which would not detrimentally affectpolishing. The disc 206 may be fabricated from a polymer, for examplefluoropolymers, PE, a TEFLON®0 material, PFA, PES, HDPE, UHMW or thelike. The disc 206 can be secured in the basin 202 using fasteners suchas screws or other means such as snap or interference fit with theenclosure, being suspended therein and the like. The disc 206 ispreferably spaced from the electrode 204 to provide a wider processwindow, thus reducing the sensitivity of depositing material andremoving material from the substrate surface to the electrode 204dimensions.

The disc 206 is generally permeable to the electrolyte 220. In oneembodiment, the disc 206 includes a plurality of perforations orchannels 222 formed therein. The perforation size and density isselected to provide uniform distribution of the electrolyte 220 throughthe disc 206 to the substrate 114. In one aspect of the disc 206includes perforations having a diameter between about 0.02 inches (0.5millimeters) and about 0.4 inches (10 mm). The perforations may have aperforation density between about 30% and about 80% of the polishingarticle. A perforation density of about 50% has been observed to provideelectrolyte flow with minimal detrimental effects to polishingprocesses. Generally, the perforations of the disc 206 and the polishingarticle 205 are aligned to provide to provide for sufficient mass flowof electrolyte through the disc 206 and polishing article 205 to thesubstrate surface. The polishing article 205 may be disposed on the disc206 by a mechanical clamp or conductive adhesive.

The electrolyte 220 is prevented from overflowing the processing area232 by a plurality of apertures 234 disposed in a skirt 254. Theapertures 234 generally provide a path through the cover 208 for theelectrolyte 220 exiting the processing area 232 and flowing into thelower portion of the basin 202. The apertures 234 are generallypositioned between a lower surface 236 of the depression 258 and thecenter portion 252. As at least a portion of the apertures 234 aretypically higher than the surface of the substrate 114 in a processingposition, the electrolyte 220 fills the processing area 232 and is thusbrought into contact with the substrate 114 and polishing article 205.Thus, the substrate 114 maintains contact with the electrolyte 220through the complete range of relative spacing between the cover 208 andthe disc 206.

The electrolyte 220 collected in the basin 202 generally flows throughthe drain 214 disposed at the bottom 210 into the fluid delivery system272. The fluid delivery system 272 typically includes a reservoir 233and a pump 242. The electrolyte 220 flowing into the fluid deliverysystem 272 is collected in the reservoir 233. The pump 242 transfers theelectrolyte 220 from the reservoir 233 through a supply line 244 to thenozzle 270 where the electrolyte 220 recycled through the ECMP station102. A filter 240 is generally disposed between the reservoir 233 andthe nozzle 270 to remove particles and agglomerated material that may bepresent in the electrolyte 220.

Polishing Article Structures

In one aspect, the polishing article 205 is composed of a single layerof conductive polishing material described-herein disposed on the disc206. In another aspect, the polishing article 205 may comprises aplurality of material layers including at least one conductive materialon the substrate surface or providing for a conductive surface forcontacting a substrate.

FIG. 3 is a cross section view of the polishing article 205 illustratinga multi-layer or composite layer polishing article having a conductivepolishing portion 310 for polishing a substrate surface and a mountingportion 320. The conductive polishing portion 310 may include aconductive polishing material or be a composite of the conductivepolishing material and the conventional polishing material describedherein. The thickness of the polishing article 205 may be between about0.1 mm and about 5 mm.

The mounting portion 320 generally comprises the same material as theconductive polishing portion 310. However, the mounting portion 320 maybe formed of other materials, such as formed only from a conventionalhard polishing material, i.e., a shore D hardness of about 80 orgreater, which provides support to the conductive polishing portion 310during polishing. Additionally, the mounting portion 320 may be aconventional soft material, such as compressed felt fibers leached withurethane, for absorbing some of the pressure applied between thepolishing article 205 and the carrier head 130. The soft material mayhave a Shore D hardness between about 25 and about 40.

Generally, the conductive polishing portion 310 is adhered to themounting portion 320 by a conventional adhesive. The adhesive may beconductive or dielectric depending on the requirements of the process.The mounting portion 320 may be affixed to the disc 206 by an adhesiveor mechanical clamps.

The conductive polishing portion 310 and the mounting portion 320 of thepolishing article 205 are generally permeable to the electrolyte by aplurality of perforations or channels formed therein. The plurality ofperforations or channels allows electrolyte to flow through and contactthe surface during processing. Perforations 350 formed in the polishingarticle 205 may include channels or apertures in the polishing articlehaving a diameter between about 0.02 inches (0.5 millimeters) and about0.4 inches (10 mm). While not shown in FIG. 3, the perforations may havea diameter about equal to the thickness of the polishing article 205, oran aspect ratio of about 1:1 between the thickness of the polishingarticle 205 and the diameter of the perforations disposed therein.

The polishing article may have a perforation density between about 30%and about 80% of the polishing article to provide for sufficient massflow of electrolyte across the polishing article surface. In oneembodiment, a perforation density of about 50% provides sufficientelectrolyte flow to facilitate uniform anodic dissolution from thesubstrate surface. Perforation density is broadly described herein asthe area or volume of polishing article that the perforations comprise,i.e., the aggregate number and diameter or size of the perforations, ofthe surface or body of the polishing article when perforations areformed in the polishing article 205.

The perforation size and density is selected to provide uniformdistribution of electrolyte through the polishing article 205 to asubstrate surface. Generally, the perforation size, perforation density,and organization of the perforations of both the conductive polishingportion 310 and the mounting portion 320 are configured and aligned toeach another to provide for sufficient mass flow of electrolyte throughthe conductive polishing portion 310 and the mounting portion 320 to thesubstrate surface.

Referring to FIG. 4, in one aspect, the polishing article 205 includesconductive polishing surface article 410 for polishing a substratesurface, a conductive article support layer 420, and a rigid supportlayer 430. Generally, the conductive polishing surface article 410 isdisposed on the conductive article support layer 420 and is adhered tothe conductive article support layer 420 by a conductive adhesive. Theconductive article support layer 420 may be affixed to the rigid supportlayer 430 by a conventional adhesive used with polishing materials andin polishing processes. The rigid support layer 430 may comprise amounting portion 440 to be disposed on a article support structure, suchas the disc 206, or may comprise the disc 206 itself. The polishingarticle 205 may be affixed to the disc 206 by an adhesive or mechanicalclamps (not shown). The thickness of the polishing article 205 isbetween about 0.1 mm and about 5 mm in thickness.

The conductive polishing surface article 410 may comprise a conductivepolishing material or composite of a conductive polishing materialdisposed in conventional polishing materials as described herein. Theconductive polishing surface article 410 generally includes a surfaceroughness of about 1 micron or less. The conductive polishing surfacearticle 410 generally has a hardness of about 50 or greater on the ShoreD Hardness scale for polymeric materials.

The conductive article support layer 420 may be made from a conductivematerial compatible with surrounding electrolyte which would notdetrimentally affect polishing. The conductive article support layer 420can be made of materials including conductive noble metals, such asplatinum, or a conductive polymer to provide electrical conductionacross the polishing article. Suitable materials for the conductivearticle support layer 420 are those which are inert materials in thepolishing process and are resistant to being consumed or damaged duringECMP.

However, the invention contemplates the use of materials for theconductive article support layer 420 that are reactive with thesurrounding electrolyte, such as copper, if such materials are isolatedfrom the surrounding electrolyte. For example, the conductive articlesupport layer 420 may be conformally covered with the conductivepolishing material to minimize any detrimental impact of reactivitybetween the material of the conductive article support layer 420 andsurrounding electrolyte.

The conductive article support layer 420 generally has a betterconductivity, i.e., lower resistivity, than does the conductivepolishing surface article 410. For example, the conductive articlesupport may comprise platinum, which has a resistivity 9.81 μΩ-cm at 0°C., and is a lower resistivity than carbon fibers or carbon nanotubes,both of which exhibit resistivities of 1.0 Ω-cm or less. The conductivearticle support layer 420 is used to provide for uniform bias or currentto minimize conductive resistance along the surface of the article, forexample, the radius of the article, during polishing for uniform anodicdissolution across the substrate surface.

The conductive article support layer 420 is connected to a power source(not shown). The conductive article support layer 420 provides thecurrent carrying capability, i.e., the anodic bias for anodicdissolution, of the conductive polishing article 205. The power sourcemay be connected to the conductive article support layer 420 by one ormore conductive contacts disposed around the conductive article supportlayer 420. One or more power sources may be connected to the conductivearticle support layer 420 by the one or more contacts to allow forgenerating variable bias or current across portion of the substratesurface.

The rigid support layer 430 generally comprises a rigid support materialused to hold polishing article. Rigid support layer 430 may includepolymeric materials, for example fluoropolymers, PE, a TEFLON®0material, PFA, PES, HDPE, UHMW or the like used for the disc 206.Additionally, the rigid support layer 430 may include a conventionalhard polishing material, for example, materials found in the IC seriesof polishing article, such as polyurethane or polyurethane composites,including the IC-1000 polishing pad, from Rodel Inc., of Phoenix, Ariz.Generally, when using a hard conventional material for the rigid supportlayer 430, the hard conventional material has a hardness less than thatof the conductive polishing surface article 410.

Alternatively, a layer of compressible material, such as soft polishingmaterial may be disposed in place of the rigid support layer 430 orbetween the conductive article support layer 420 and rigid support layer430. The compressible material includes a conventional soft material,such as compressed felt fibers leached with urethane, and having a ShoreD hardness between about 25 and about 40.

The conductive polishing surface article 410, the conductive articlesupport layer 420, and the rigid support layer 430 of the polishingarticle 205 are generally made permeable to the electrolyte by aplurality of perforations or channels formed therein. The perforations405 include channels or apertures in the polishing article having adiameter between about 0.02 inches (0.5 millimeters) and about 0.4inches (10 mm) and a perforation density may be between about 30% andabout 80% of the polishing article 205. A perforation density of about50% may be used with the polishing article 205. While not shown in FIG.4, the perforations 405 may have a diameter about equal to the thicknessof the polishing article 205, or an aspect ratio of about 1:1 betweenthe thickness of the polishing article 205 and the diameter of theperforations disposed therein.

Generally the perforation size, organization, and density of theconductive polishing surface article 410, the conductive article supportlayer 420, and the rigid support layer 430 are configured and aligned toprovide for sufficient mass flow of electrolyte through rigid supportlayer 430, the conductive article support layer 420, and the conductivepolishing surface article 410 to the substrate surface.

In one embodiment, the rigid support 430 includes a surface for mountingon disc 206. The disc 206 may be perforated. The rigid support 430 maybe secured to the disc 206 by mechanical clamps or a conventionaladhesion for securing polishing materials to support structures.Generally, the perforations of the disc 206 are configured and alignedwith the rigid support 430, the conductive article support layer 420,and the conductive polishing surface article 410 to provide forsufficient mass flow of electrolyte through the polishing article 205and the disc 206 to the substrate surface.

FIG. 5A is a side schematic view of another embodiment of the polishingarticle 205 disposed on the disc 206. The polishing article 205 in thisembodiment includes a round polishing pad including conductive polishingsurface article 510 disposed on a article support layer 520, which isdisposed on a support layer 530. The conductive polishing surfacearticle 510 includes carbon fibers and polyurethane, the article supportlayer 520 includes a platinum film, and the support 530 typicallyincludes a compressible material, such as a soft material describedherein, including compressed felt fibers leached with urethane. A lesscompressible material, such as a hard material described herein, forexample, polyurethane, may be used as the support layer 530. Grooves 550are formed in the conductive polishing surface article 510, theconductive article support layer 520, and the rigid support 530 of thepolishing article 205, and perforations 505 are formed in the disc 206to further allow electrolyte to contact the substrate surface duringECMP.

FIG. 5B is a side schematic view of another embodiment of the polishingarticle 205 disposed on disc 206. In this embodiment, the conductivearticle support layer 520 layer is isolated from the surroundingelectrolyte 560 by a conformal layer of the conductive polishing surfacearticle 510. The conductive polishing surface article 510 is provided ata thickness of about 1 mm and covers the entire exposed conductivearticle support layer 520. Since the conductive article support layer520 is not exposed to the surrounding electrolyte, the conductive layer520 may include materials, such as copper which has a resistivity of 1.6μΩ-cm at 0° C., that may be consumed if exposed to ECMP processing.

While not shown in FIGS. 5A and 5B, the perforations 505 may have adiameter about equal to the thickness of the polishing article 205 or anaspect ratio of about 1:1 between the thickness of the polishing article205 and the diameter of the perforations disposed therein.

FIG. 6 is a side schematic view of another embodiment of the polishingarticle 205 disposed on the disc 206. A metal mesh 610 of a conductivemetal is disposed in the polishing article 205 to provide conductivityto the polishing article 205. In one embodiment, the polishing article205 using a metal mesh generally comprise a stack of polishing materialsincluding metal mesh 610 disposed in a first conventional polishingmaterial, a flexible polishing material 620, and rigid support 630 of asecond conventional polishing material. The metal mesh 610 disposed inthe first conventional polishing material includes the conductivepolishing portion of the polishing article 205 and the flexiblepolishing material 620 and rigid support 630 comprise the mountingportion of the polishing article 205.

The amount, thickness, material, and configuration of the metal mesh andthe thickness of the conventional polishing material are designed toprovide a bias or current to the substrate surface with minimalresistance between an external power source and the polishing articlesurface. For example, the metal mesh may be interwoven wire forming a“X-Y” grid (a square pattern) or a triangular pattern, an “X-Y” gridwith diagonal wires passing therethrough, formed in the conventionalpolishing material.

The metal mesh includes conductive materials, such as platinum describedherein, which is chemically inert to the surrounding electrolyte.Additionally, conformal coverage of the metal mesh by the conventionalor conductive polishing material may allow the use of materials, such ascopper which has a resistivity of 1.6 μΩ-cm at 0° C., that may beconsumed if exposed to ECMP processing.

The conductive polishing article 610 with the metal mesh may bemanufactured by forming a pattern in the first conventional polishingmaterial and then electroplating or pressing a metal mesh in thepattern. The conductive polishing article 610 may also be manufacturedto be conformally covered by the conventional polishing material bydisposing the metal mesh in an injection molding apparatus and thenforming the conventional polishing material around the mesh by aninjection molding process. Grooves 650 and perforations 605 may alsoformed in the polishing article 205 with the metal mesh for effectiveflow of electrolyte across the polishing article 205. The metal mesh isgenerally formed in the conductive polishing article 610 with exposedcontacts for connecting to a power source.

The conventional polishing material used with the metal mesh 610 and theconventional polishing material of the rigid support 630 may be the sameor different conventional material. The conventional polishing materialused with the metal mesh 610 and the conventional polishing material ofthe rigid support 630 may have the same or different hardness. Forexample, a first conventional polishing material may be used with themetal mesh 610 may have a Shore D hardness between about 50 and about60, and the rigid support 630 may be formed by a second conventionalpolishing material having a hardness of about 80. Conductive materials,such as conductive polymers and conductive filler material, may also beused with the metal mesh 610.

The flexible polishing material 620 may comprise a uniformlycompressible plastic, foam or rubber. An example of a flexible polishingmaterial is compressed felt fibers leached with urethane. One polishingarticle material suitable for use as the flexible polishing material 620includes the materials used in the Politex or Suba IV polishing articlefrom Rodel, Inc. of Phoenix, Ariz. (Politex and Suba IV are productnames of Rodel, Inc.). The flexible polishing material may have a ShoreD hardness between about 25 and about 40.

Referring back to FIGS. 5A, 5B, and 6, grooves may be disposed in thepolishing article 205 to promote electrolyte flow to the substratesurface for anodic dissolution or electroplating processes. While thegrooves shown in FIGS. 5A, 5B, and 6, illustrate grooves throughmultiple layers, the invention contemplates grooves being formed in theupper layer or polishing surface that contacts the substrate surfacewith perforations in the non-grooved layer to provide electrolyte flowtherethrough.

Examples of grooves used to facilitate electrolyte flow include lineargrooves, arcuate grooves, annular concentric grooves, and helicalgrooves among others. The grooves formed in the article 205 may have across-section that is square, circular, semi-circular, or any othershape conventionally used in the art. The grooves may be configured intopatterns, such as an X-Y pattern disposed on the polishing surface or atriangular pattern formed on the polishing surface, or combinationsthereof, to improve electrolyte flow over the surface of the substrate.Any suitable groove configuration, size, diameter, and spacing may beused to provide the desired flow of electrolyte. In one aspect of thepolishing article, the grooves are configured to intersect with theperforations formed in the polishing article.

FIG. 7 is a top plan view of one embodiment of a grooved polishingarticle. A round pad 740 of the polishing article 205 is shown having aplurality of perforations 746 of a sufficient size and organization toallow the flow of electrolyte to the substrate surface. The perforations746 can be spaced between about 0.2 inches and about 1.0 inches from oneanother. The perforations may be circular perforations having a diameterof between about 0.02 inches (0.5 millimeters) and about 0.4 inches (10mm). Further the number and shape of the perforations may vary dependingupon the apparatus, processing parameters, and ECMP compositions beingused.

Grooves 742 are formed in the polishing surface 748 of the polishingarticle 205 therein to assist transport of fresh electrolyte from thebulk solution from basin 202 to the gap between the substrate and thepolishing article. The grooves 742 may be spaced between about 30 milsand about 300 mils apart from one another. Generally, grooves 742 formedin the polishing article have a width between about 5 mils and about 30mils, but may vary in size as required for polishing. An example of agroove pattern includes grooves of about 10 mils wide spaced about 60mils apart from one another. Transport of electrolyte may be enhanced byforming the perforations at least partially in the grooves to improveflow of the electrolyte.

The grooves 742 may have various patterns, including a groove pattern ofsubstantially circular concentric grooves on the polishing surface 748as shown in FIG. 7, an X-Y pattern as shown in FIG. 8 and a triangularpattern as shown in FIG. 9. While these patterns are shown and describedherein, the invention contemplates the use of other patterns which canfacilitate electrolyte flow to a substrate surface during processing.

FIG. 8 is a top plan view of another embodiment of a polishing padhaving grooves 842 disposed in an X-Y pattern on the polishing article848 of a polishing pad 840. Perforations 846 may be disposed at theintersections of the vertically and horizontally disposed grooves, andmay also be disposed on a vertical groove, a horizontal groove, ordisposed in the polishing article 848 outside of the grooves 842.

The perforations 846 and grooves 842 are disposed in the inner diameter850 of the polishing article and the outer diameter 850 of the polishingpad 844 may be free of perforations and grooves and perforations.

FIG. 9 is another embodiment of patterned polishing article 948. In thisembodiment, grooves 942 may be disposed in an X-Y pattern withdiagonally disposed grooves 945 intersecting the X-Y patterned grooves942. The diagonal grooves 945 may be disposed at an angle between about30° and about 60° from any of the X-Y grooves 942. Perforations 946 maybe disposed at the intersections of the X-Y grooves 942, theintersections of the X-Y grooves 942 and diagonal grooves 945, along anyof the grooves 942 and 945, or disposed in the polishing article 948outside of the grooves 942 and 945. The perforations 946 and grooves 942are disposed in the inner diameter 950 of the polishing article and theouter diameter 950 of the polishing pad 944 may be free of perforationsand grooves.

It is believed that the grooves provide a supply of electrolyte to thesubstrate surface that is evenly distributed on the substrate surfaceallowing for a more even dissolution of material into the substrate, andthereby increasing substrate planarity and uniformity. It is furtherbelieved that the use of intersecting grooves and perforations willallow electrolyte to enter through one set of perforation, be evenlydistributed around the substrate surface, and then removed through asecond set of perforations.

Conductive Elements in Polishing Articles

The conductive polishing article 205 of the invention may alternativelycomprise discrete conductive elements disposed in a polishing material.While not shown, the following polishing article descriptions mayinclude polishing articles having perforation and grooving patternsdescribed herein and shown in FIGS. 7-9, with configurations to thepatterns to incorporate the conductive elements described herein asfollows.

FIG. 10A depicts one embodiment of a polishing article 205 havingconductive elements disposed therein. The polishing article 205generally comprises a body 1006 having a polishing surface 1002 adaptedto contact the substrate while processing. The polishing surface 1002has one or more opening or pockets 1004 formed therein to at leastpartially receive the conductive elements 1065. The conductive elements1065 are generally disposed to have a contact surface 1008 with asubstrate that extends above a plane defined by the polishing surface1002. The contact surface 1008 is typically configured, such as byhaving a compliant, flexible, or pressure moldable surface, to maximizeelectrical contact of the conductive elements 1065 when contacting thesubstrate. During polishing, a bias force that urges the contact surface1008 into a position co-planar with the polishing surface 1002.

The body 1006 is generally made permeable to the electrolyte by aplurality of perforations 1010 formed therein as described herein. Thepolishing article 205 may have an aperture density between about 30% andabout 80% of the surface area of the polishing article 205 to providefor sufficient mass flow of electrolyte across the polishing surface1002. In one embodiment, an aperture density of about 50% providessufficient electrolyte flow to facilitate uniform anodic dissolutionfrom the substrate surface.

The body 1006 generally comprises a dielectric material such as theconventional materials described herein. The pockets 1004 formed in thebody 1006 are generally configured to retain the conductive elements1065 while processing, and accordingly may vary in shape andorientation. In the embodiment depicted in FIG. 10A, the pockets 1004are grooves of rectangular cross section and are disposed across thepolishing surface 1002 coupling two points on the perimeter of thepolishing article 205. Alternatively, the pockets 1004 (and conductiveelements 1065 disposed therein) may be disposed at irregular intervals,be orientated radially, perpendicular and may additionally be linear,curved, concentric, involute curves or other orientation.

The conductive elements 1065 disposed in the body 1006 are generallyprovided to produce a bulk resistivity or a bulk surface resistivity ofabout 10 Ω-cm or less. In one aspect of the polishing article, thepolishing article has a resistivity of about 1 Ω-cm or less. Theconductive elements 1065 generally have mechanical properties that donot degrade under sustained electric fields and are resistant todegradation in acidic or basic electrolytes. In one embodiment, theconductive elements 1065 are sufficiently compliant or flexible as tomaintain electrical contact between the entire contact surface 1008 andthe substrate during processing. Sufficient compliant or flexiblematerials for the conductive element 1065 may have an analogous hardnessof about 80 or less on the Shore D Hardness scale compared to thepolishing material. A conductive element 1065 having an analogoushardness of about 50 or less on the Shore D Hardness scale for polymericmaterials may be used.

In the embodiment depicted in FIG. 10A, the conductive elements 1065 areembedded in the polishing surface 1002 in a parallel, spaced-apartrelation at regular intervals. At least one perforation 1010 is formedthrough the polishing article 205 between each conductive element 1065.An example of the conductive elements 1065 include conductive andcompliant tubing fabricated from silicon filled with nickel-coatedcarbon. The conductive elements may also extend over only a portion ofthe width or diameter of the substrate surface, rather than across theentire surface of the polishing pas as shown in FIG. 10A.

In another embodiment depicted in FIG. 10B, the conductive elements 1065are comprised of a spring 1090 disposed in groove 195. The spring 1090is fabricated or coated with an at least partially conductive materialas described herein. The spring 1090 may extend above the polishingsurface 1002 from the groove 195.

A connector 1030 is utilized to couple the conductive elements 1065 to apower source (not shown) to electrically bias the conductive elements1065 while processing. The connector 1030 is generally a wire, tape orother conductor compatible with process fluids or having a covering orcoating that protects the connector 1030 from the process fluids. Theconnector 1030 may be coupled to the conductive elements 1065 bysoldering, stacking, brazing, clamping, crimping, riveting, fastening,conductive adhesive or by other methods or devices. Examples ofmaterials that may be utilized in the connector 1030 include insulatedcopper, graphite, titanium, platinum, gold, and HASTELOY® among othermaterials.

Coatings disposed around the connectors 1030 may include polymers suchas fluorocarbons, PVC and polyimide. In the embodiment depicted in FIG.10A, one connector 1030 is coupled to each conductive element 1065 atthe perimeter of the polishing article 205. Alternatively, theconnectors 1030 may be disposed through the body 1006 of the polishingarticle 205. In yet another embodiment, the connector 1030 may becoupled to a conductive grid (not shown) disposed in the pockets and/orthrough the body 1006 that electrically couples the conductive elements1065.

FIG. 10C illustrates another embodiment of the polishing article 205having conductive elements 1065 comprising a conductive structure 1075embedded in a conductive filler 1080, such as a conductive polymericmaterial as described above, including conductive polyurethanematerials, disposed in the body 1006, which comprises a dielectricmaterial, such as polyurethane. The conductive elements 1075 may beembedded in the body 1006 a parallel, spaced-apart relation at regularintervals. The conductive filler 1080 is generally planar with thepolishing surface 1002. At least one perforation 1010 is formed throughthe polishing article 205 between each conductive element 1075. Anexample of the conductive element 1075 includes copper wire or tubing ina conductive polyurethane filler disposed in a body of polyurethane. Asub-pad 1085 may be disposed beneath the body 1006 and in contact withthe conductive filler 1080. The sub-pad 1085 may be perforated and isprimarily used to provide support for the body 1006 and the conductiveelements 1075 disposed therein. The conductive elements may also extendover only a portion of the width or diameter of the substrate surface,rather than across the entire surface of the polishing pas as shown inFIG. 10C.

FIG. 11A depicts another embodiment of a conductive member 1100 disposedin the pocket 1004 of the polishing article 205. The conductive member1100 is generally an at least partially conductive bar, cylinder or coilthat includes a contact surface 1102 that extends above a plane definedby the polishing surface 1002 of the body 1006. The contact surface 1102is generally rounded to prevent damage to the substrate duringprocessing.

A biasing member 1104 is disposed between the conductive member 1100 andthe body 1006. The biasing member 1104 generally provides a bias thaturges the conductive member 1100 away from the body 1006. The biasingmember 1104 is comprised of a resilient material or device and may be acompression spring, flat spring, coil spring, a foamed polymer such asfoamed polyurethane (e.g., PORON®), an elastomer, a bladder or othermember or device that urges the conductive member 1100.

FIG. 11B depicts another embodiment of a conductive member 1150 disposedin the pocket 1004 of the polishing article 205. The conductive member1150 is generally comprises a plurality of balls or pins 1154. The pins1154 are at least partially comprised and/or coated with an at leastpartially conductive material as described herein. Each pin 1154includes a contact surface 1152 that extends above a plane defined bythe polishing surface 1002 of the body 1006. The contact surface 1152 isgenerally rounded to prevent damage to the substrate during processing.

The pins 1154 are disposed through a bushing 1156 disposed in the pocket1004. The pins 1154 may move through the bushing 1156 so that thecontact surface 1152 of the pins 1154 may become coplanar with thepolishing surface 1002 when polishing.

A biasing member 1158 is disposed between the conductive member 1150 andthe body 1006. The biasing member 1158 generally provides a bias thaturges the conductive member 1150 away from the body 1006. The biasingmember 1158 is comprised of a resilient material or device and may be acompression spring, flat spring, coil spring, a foamed polymer such asfoamed polyurethane (e.g., PORON®), an elastomer, a bladder or othermember or device that urges the conductive member 1150. Typically, atleast one of the biasing member 1158 or the bushing 1156 comprises aconductive material or coating to electrically couple the pins 1154.

FIGS. 12A-B depict alternative embodiments of a conductive member 1200disposed in the pocket 1004 of the polishing article 205. The conductivemember 1200 generally includes a carrier 1202 and a contact member 1204.A biasing member 1206 similar to the biasing member 1104 describedherein is disposed between the carrier 1202 and body 1006 of thepolishing article 205 for urging the contact member 1204 to a positionat least partially above a plane defined by the polishing surface 1002of the body 1006.

The carrier 1202 is typically formed from a conductive material such asgraphite or a metal or other material compatible with processchemistries as described herein. Alternatively, other materials such assemiconductors or dielectric may be utilized. The carrier 1202 isconfigured to remain in contact with the contact member 1204 duringprocessing.

The contact member 1204 is typically formed from a conductive materialsuch as graphite or a metal or other at least partially conductivematerial compatible with process chemistries as described herein. Thecontact member 1204 is typically a cylinder, coil, bar or ball althoughother shapes may be utilized. For example, the contact member 1204 is agraphite rod seated on a graphite carrier 1202 in the embodimentdepicted in FIG. 12A and the contact member 1204 is a plurality ofgraphite or gold balls seated on and electrically coupled through agraphite carrier 1202 in the embodiment depicted in FIG. 12B.

FIG. 13 depicts another embodiment of a polishing material 1300. Thepolishing material 1300 includes a body 1302 having one or more at leastpartially conductive elements 1304 disposed on a polishing surface 1306.The conductive elements 1304 generally comprise a plurality of fibers,strands, and/or flexible fingers with contact the substrate whileprocessing. The conductive elements 1304 is comprised an at leastpartially conductive materials as described herein. In the embodimentdepicted in FIG. 13, the conductive elements 1304 are a brush comprisesa plurality of conductive sub-elements 1313 coupled to a base 1309. Theconductive sub-elements 1313 include electrically conductive fibers,such as carbon fibers or other conductive, compliant (i.e., flexible)made from a conductive material described herein. The base 1309 alsocomprises an electrically conductive material and is coupled to aconnector 1030.

The conductive elements 1304 generally are disposed in a pocket 1308formed in the polishing surface 1306. The conductive elements 1304 maybe orientated between 0 and 90 degrees relative to the polishing surface1306. In embodiments where the conductive elements 1304 are orientatedparallel to the polishing surface 1306, the conductive elements 1304 maypartially be disposed on the polishing surface 1306.

The pockets 1308 have a lower mounting portion 1310 and an upper,clearance portion 1312. The mounting portion 1310 is configured toreceive the base 1309 of the conductive elements 1304, and retain theconductive elements 1304 by press fit, clamping, adhesives or by othermethods. The clearance portion 1312 is disposed where the pocket 1308intersects the polishing surface 1306. The clearance portion 1312 isgenerally larger in cross section than the mounting portion 1310 toallow the conductive elements 1304 to flex when contacting a substratewhile polishing without being disposed between the substrate and thepolishing surface 1306.

FIG. 14A depicts one embodiment of a brush 1400 comprised of conductiveelements 1402 (only four are shown for clarity). The brush 1400 isgenerally orientated between 0 to 90 degrees relative to a polishingsurface 1404 and can be inclined in any polar orientation relative aline normal to the polishing surface 1404.

Each conductive element 1402 generally comprises a loop or ring 1406having a first end 1408 and a second end 1410 disposed in a pocket 1412formed in the polishing surface 1404. Each conductive element 1402 istypically coupled to an adjoining conductive element to form a pluralityof loops 1406 extending above the polishing surface 1404. In theembodiment depicted in FIG. 14A, each loop 1406 is fabricated fromgraphite or conductive metal, such as gold, and are coupled by a tiewire base 1414 adhered to the pocket 1412. The contact height of theloop 1406 above the polishing surface is between about 1 millimeter andabout 2 millimeters and the diameter of the material comprising the loopis between about 1 mil (thousandths of an inch) and about 2 mils. Thetie wire base 1414 may be a conductive material, such as titanium. Thetie wire base 1414 may also be coated in a layer of conductive material,such as copper, that dissolves from the polishing pad article duringpolishing.

FIG. 14B depicts another embodiment of a brush 1400 having a conductingsurface 1440 and a plurality of discreet conductive elements 1402 formedthereon. The conductive elements 1402 generally comprise fibers of aconductive material, such as carbon, vertically displaced from theconducting surface 1440 of the polishing article 205 and horizontallydisplaced from each other. The conducting elements 1402 of the brush1400 are generally orientated between 0 to 90 degrees relative to aconducting surface 1440 and can be inclined in any polar orientationrelative a line normal to the conducting surface 1440. The conductiveelements 1402 may be formed across the length of the polishing pads, asshown in FIG. 14B or may only be partially disposed in the polishingpad. The contact height of the conductive elements 1402 above thepolishing surface may be up to about 5 millimeters and the diameter ofthe material comprising the conductive element 1402 is between about 1mil (thousandths of an inch) and about 2 mils. The height above thepolishing surface and the diameter of the conductive elements 1402 mayvary upon the polishing process being performed.

Alternatively, the conducting elements 1402 may comprise a conductingwire of copper, platinum, platinum-coated copper, aluminum, orcombinations thereof. The conducting surface 1440 may comprise a metalmaterial, such as a copper sheet, a platinum sheet, or a platinum coatedcopper sheet.

The fibers of the conductive elements 1402 are compliant enough todeform under a contact pressure while maintaining an electrical contactwith a substrate surface with reduced or minimal scratching of thesubstrate surface. Generally, the substrate surface only contacts theconductive elements 1402 of the polishing article 205. The conductiveelements 1402 are positioned so as to provide a uniform current densityover the surface of the polishing article 205.

The conductive elements 1402 are adhered to the conducting surface by anon-conductive, or dielectric, adhesive or binder. The non-conductiveadhesive may provide a dielectric coating to the conducting surface 1440to provide an electrochemical barrier between the conducting surface1440 and any surrounding electrolyte. The conducting surface 1440 may bein the form of a round polishing pad or a linear web or belt ofpolishing article 205. A series of perforations (not shown) may bedisposed in the conducting surface 1440 for provided flow of electrolytetherethrough.

While not shown, the conductive plate may be disposed on a support padof conventional polishing material for positioning and handling of thepolishing article 205 on a rotating or linear polishing platen.

FIG. 14C shows another embodiment of a brush 1400 having a pluralityconductive elements 1402, disposed in a radial pattern from the centerof the substrate to the edge. The plurality of conductive elements maybe displaced from each other at intervals of 15°, 30°, 45°, 60°, and 90°degrees, or any other combinations desired. The conductive elements 1402are generally spaced to provide as uniform application of current orpower for polishing of the substrate. The conductive elements may befurther spaced so as to not contact each other. Wedge portions 1404 of adielectric polishing material of the body 1006 may be configured toelectrically isolate the conductive elements 1402. A spacer or recessedarea 1460 is also formed in the polishing article to also isolate theconductive elements 1402 from each other. The conductive elements 1402may be in the form of loops as shown in FIG. 14A or vertical extendingfibers as shone in FIG. 14B.

FIG. 14D shows another embodiment of forming the conductive elements1402 having loops 1406 formed therein and securing the conductiveelements to the body 1006 of the polishing article. Passages 1450 areformed in the body 1006 of the polishing article intersecting grooves1470 for the conductive elements 1402. An insert 1455 is disposed in thepassages 1450. The insert 1455 comprises a conductive material, such asgold or the same material as the conductive element 1406. Connectors1030 may then be disposed in the passages 1450 and contacted with theinsert 1455. Ends 1475 of the conductive element 1402 may be contactedwith the insert 1455 for flow of power therethrough. The ends 1475 ofthe conductive element 1402 and the connectors 1030 are then secured tothe conductive insert 1455 by dielectric inserts 1460. The inventioncontemplated using the passages for every loop 1406 of the conductiveelement 1402, at intervals along the length of the conductive element1402, or only at the extreme ends of the conductive element 1402.

Further examples of conductive polishing pads are described in U.S.Provisional Patent Application Ser. No. 60/258,162, filed Dec. 22, 2001,which is incorporated by reference to the extent not inconsistent withthe aspects and claims herein.

Conductive Polishing Article Processing

In operation, the polishing article 205 is disposed on the disc 206 inan electrolyte in the basin 202. A substrate 114 on the polishing headis disposed in the electrolyte and contacted with the polishing article205. Electrolyte is flowed through the perforations of the disc 206 andthe polishing article 205 and is distributed on the substrate surface bygrooves formed therein. Power from a power source is then applied to theconductive polishing article 205 and the electrode 204, and conductivematerial, such as copper, in the electrolyte is then removed by ananodic dissolution method.

The substrate 114 and polishing article 205 are rotated relative to oneanother to polish the substrate surface. When contacting the substratesurface, the polishing article 205 typically applies a pressure of about6 psi or less to the substrate surface. A pressure between of about 2psi or less is used with substrate containing low dielectric constantmaterial between the substrate 114 and the polishing article 205 duringpolishing of the substrate.

Electrolyte solutions may include commercially available electrolytes.For example, in copper containing material removal, the electrolyte mayinclude sulfuric acid based electrolytes or phosphoric acid basedelectrolytes, such as potassium phosphate (K₃PO₄), or combinationsthereof. The electrolyte may also contain derivatives of sulfuric acidbased electrolytes, such as copper sulfate, and derivatives ofphosphoric acid based electrolytes, such as copper phosphate.Electrolytes having perchloric acid-acetic acid solutions andderivatives thereof may also be used. Additionally, the inventioncontemplates using electrolyte compositions conventionally used inelectroplating or electropolishing processes, including conventionallyused electroplating or electropolishing additives, such as brightenersamong others. In one aspect of the electrolyte solution, the electrolytemay have a concentration between about 0.2 and about 1.2 Molar of thesolution.

As one example, copper sulfate (CuSO₄) can be used as the electrolyte.One source for electrolyte solutions used for electrochemical processessuch as copper plating, copper anodic dissolution, or combinationsthereof is Shipley Leonel, a division of Rohm and Haas, headquartered inPhiladelphia, Pa., under the tradename Ultrafill 2000.

In anodic dissolution, the bias is applied between the electrode 204,performing as a cathode, and the conductive article support layer 520 ofthe polishing article 205, performing as the anode. The substrate incontact with the polishing article is polarized via the conductivepolishing surface article 510 at the same time the bias is applied tothe conductive article support member. The application of the biasallows removal of conductive material, such as copper-containingmaterials, formed on a substrate surface. The bias may include theapplication of a voltage of about 15 volts or less to the substratesurface. A voltage between about 0.1 volts and about 10 volts may beused to dissolve copper-containing material from the substrate surfaceand into the electrolyte.

Alternatively, the bias may be a current density between about 0.1milliamps/cm² and about 50 milliamps/cm², or between about 0.1 amps toabout 20 amps for a 200 mm substrate. It is believed that biasing thesubstrate from the polishing article 205 provides uniform dissolution ofconductive materials, such as metals, into the electrolyte from thesubstrate surface as compared to the higher edge removal rate and lowercenter removal rate from conventional edge contact-pins bias.

The bias applied to perform the anodic dissolution process may be variedin power and application depending upon the user requirements inremoving material from the substrate surface. For example, a timevarying anodic potential may be provided to the conductive polishingarticle 205. The bias may also be applied by electrical pulse modulationtechniques. The electrical pulse modification technique comprisesapplying a constant current density or voltage over the substrate for afirst time period, than applying a constant reverse voltage over thesubstrate for a second time period, and repeating the first and secondsteps. For example, the electrical pulse modification technique may usea varying potential from between about −0.1 volts and about −15 volts tobetween about 0.1 volts and about 15 volts.

Conductive material, such as copper containing material can be removedfrom at least a portion of the substrate surface at a rate of about15,000 Å/min or less, such as between about 100 Å/min and about 15,000Å/min. In one embodiment of the invention where the copper material tobe removed is less than 5,000 Å thick, the voltage may be applied to theconductive polishing article 205 to provide a removal rate between about100 Å/min and about 5,000 Å/min.

Power may be coupled into the polishing articles 205 described above byusing a power transference device, such as a power inlet bar, forconductive polishing materials that do not have readily available powercoupling points, such as a polishing material comprising carbon fibersor carbon nanotubes disposed in polyurethane. A power transferencedevice is typically configured to provide a linear voltage reduction inequipotent lines to the polishing material. The highest potential isclosest to the power inlet bar and the lowest potential is furthest fromthe power inlet bar. The power transference device typically has agreater conductivity than the conductive material, such as metal, i.e.,platinum or copper. The polishing article may be of any possible shape,i.e., a round polishing pad or linear belt, and the power transferencedevice may be of any shape, such as a bar inlet bar or conductive mesh.The power transference device usually has a substrate facing side atleast as wide or long as the diameter of the substrate.

Substrate rotation on the polishing pad will equalize or average out thepotential imparted to the substrate surface during polishing to providefor more uniform material deposition rate or removal rate. The substratemay move or “sweep” parallel to the power inlet bar to provide forimproved polishing without detrimentally affecting uniformity indeposition rates or removal rates. Perpendicular movement is alsocontemplated for polishing.

The power transference device can be located either outside theelectrolyte or immersed in the electrolyte if properly composed of orencapsulated with a material that will not react with the surroundingelectrolyte as described for the conductive materials above. Forexample, a copper power inlet bar may be used for providing powerexternal of an electrolyte and a platinum power inlet bar or platinumcovered copper power inlet bar may be used submerged in an electrolytesolution. The power pad is connected to a power source via a power cord.

FIGS. 15A-15C illustrate one embodiment of a power inlet bar disposed onpolishing article described herein. FIG. 15A is a schematic side view ofa power inlet bar 1510 disposed on an edge portion of a conductiveperforated polishing material 1520. The power inlet bar 1510 is coupledto a power source (not shown) by a power cord 1530.

FIG. 15B illustrates the power inlet bar 1510 disposed on a linear beltor web 1550 of conductive, perforated polishing material 1520.Equipotent lines 1560 of the linear voltage reduction from the power baracross the conductive, perforated polishing material 1520 in equipotentlines is shown in relationship to a substrate 1570 being rotatedcounter-clockwise. FIG. 15C illustrates one embodiment of a power inletbar 1510 being mounted on a round polishing pad 1580 of conductive,perforated polishing material 1520. Both figures depict the power inletbar 1510 as wider than the diameter of the substrate to be polished.

FIG. 15D shows an alternative embodiment supplying power to theconductive elements 1590. A power strip 1530 is connected to a powersource 1535 and a side of the polishing material 1520. The power strip1530 and polishing material 1520 are configured to electrically conductpower from the power strip 1530 and the conductive elements 1590 duringrotation of the polishing pad. For example, the conductive element 1590has an exposed contact on the side of the polishing material 1520 forcontacting the power strip 1530. The power strip 1530 may comprise aconductive tape, such as copper tape. The conductive elements 1590 andpower strip 1530 are electrically connected for between about 20% and60%, for example, about 40%, of the rotation period of the polishingmaterial 1520.

Polishing Pad Materials

The conductive polishing material may include conductive polymers,polymer composites with conductive materials, conductive metals,conductive fillers or conductive doping materials, or combinationsthereof. Alternatively, the conductive polishing material may form acomposite of a conductive polishing material as a polishing layerdisposed on a conventional, dielectric, polishing material as a supportlayer.

Conductive polymers include polymeric materials that are intrinsicallyconductive, such as polyacetylene, polyethylenedioxythiophene (PEDT),which is commercially available under the trade name Baytron™,polyaniline, polypyrrole, and combinations thereof. Another example of aconductive polymer is silicon filled with nickel-coated carbon.

The polymer composites with conductive materials include polymer-noblemetal hybrid materials. Polymer-noble metal hybrid materials that may beused as the conductive polishing material described herein are generallychemically inert with a surrounding electrolyte, such as those withnoble metals that are resistant to oxidation. An example of apolymer-noble metal hybrid material is a platinum-polymer hybridmaterial. The invention contemplates the use of polymer-noble metalhybrid materials that are chemically reactive with a surroundingelectrolyte when the polymer-noble metal hybrid material is insulatedfrom a surrounding electrolyte by another material.

The conductive polishing material may include conductive metals.Conductive metals that may be used as the polishing material are thosemetals that are relatively inert to chemical reactions with thesurrounding electrolyte. Platinum is an example of a conductive metalthat may be used as the polishing material. The conductive metals mayform a portion or the entire polishing surface of the polishingmaterial. When forming a portion of the polishing surface, theconductive metals are typically disposed in a conventional polishingmaterial.

The conductive polishing materials may further include conductivefillers or conductive doping materials disposed in a binder material,such as the conductive polymers described herein or a conventionalpolishing material. Examples of conductive fillers include carbonpowder, carbon fibers, carbon nanotubes, carbon nanofoam, carbonaerogels, and combinations thereof. Carbon nanotubes are conductivehollow filaments of carbon material having a diameter in the micron andnanometer size range. The conductive fillers or conductive dopingmaterials are disposed in the binding material in an amount sufficientto provide a polishing article having a desired conductivity. The bindermaterial is typically a conventional polishing material.

The conductive material may alternatively be a conductive or dielectricmaterial at least partially coated or covered with an at least partiallyconductive material such as those described herein. For example, theconductive material may be gold plated dielectric materials. Conductivematerials may include other conductive materials and/or metals that arerelatively inert to chemical reactions with the surrounding electrolyte.One material that may be used is graphite.

Composites of conductive and conventional polishing materials includeconductive polishing materials disposed in a conventional polishingmaterial or a conductive material layer disposed on a conventionalpolishing material. Conventional polishing materials are generallydielectric materials and may include polymeric materials, such aspolyurethane, polycarbonate, polyphenylene sulfide (PPS), orcombinations thereof, and other polishing materials used in polishingsubstrate surfaces. The conventional polishing material may also includefillers and/or be in a foamed state.

An exemplary conventional material includes dielectric material, such aspolyurethane and polyurethane mixed with fillers, found in the IC seriesof polishing article, including IC-1010, which are commerciallyavailable from Rodel Inc., of Phoenix, Ariz. The invention furthercontemplates the use of other conventional polishing materials, such asa layer of compressible material. The compressible material includes aconventional soft material, such as compressed felt fibers leached withurethane.

Mechanical properties of the conventional polishing materials used inthe conductive polishing article herein provide, for example, a hardnessof about 50 or greater on the Shore D Hardness scale for polymericmaterials as described and measured by the American Society for Testingand Materials (ASTM), headquartered in Philadelphia, Pa.

Generally, the conductive polishing material or the composite of theconductive polishing material and conventional polishing material areprovided to produce a conductive polishing article having a bulkresistivity or a bulk surface resistivity of about 10 Ω-cm or less. Inone aspect of the polishing article, the polishing article has aresistivity of about 1 Ω-cm or less. An example of the conductivepolishing material is a layer of platinum, which has a resistivity 9.81μΩ-cm at 0° C., disposed on a layer of polyurethane.

The composite of the conductive polishing material and conventionalpolishing material may include between about 5 wt. % and about 60 wt. %of conductive polishing material in the polishing article 205. Anexample of a composite of the conductive polishing material andconventional polishing material includes carbon fibers or carbonnanotubes, both of which exhibit resistivities of 1 Ω-cm or less,disposed in a conventional polishing material of polycarbonate orpolyurethane in sufficient amounts to provide a polishing article havinga bulk resistivity of about 10 Ω-cm or less.

Examples of conductive material in the polishing articles 205 describedabove are the following. Referring back to FIGS. 3 and 4, an example ofthe conductive polishing portion 310 or conductive polishing surfacearticle 410 includes between about 5 wt. % and about 60 wt. % of carbonfibers or carbon nanotubes disposed in a conventional polishing materialof polycarbonate or polyurethane. The carbon fibers or carbon nanotubesare generally provided in sufficient amounts to produce a conductivepolishing surface article 410 having a bulk resistivity of about 10 Ω-cmor less. Another example of the polishing article 205 is a layer ofplatinum forming the conductive polishing portion 310 or conductivepolishing surface article 410 disposed on a layer of polyurethane.

Referring back to FIG. 6, an example of the polishing surface includes ametal mesh of platinum, gold, or platinum coated copper in aconventional polishing material of polyurethane. The metal meshproviding a bulk resistivity of about 10 Ω-cm or less.

The conductive polishing materials and the conventional polishingmaterials generally have mechanical properties which do not degradeunder sustained electric fields and are resistant to degradation inacidic or basic electrolytes. Generally, the conductive polishingmaterials and the composite of conductive polishing materials andconventional polishing materials have mechanical properties similar tothat of conventional polishing materials alone. For example, thecombination of materials has a hardness of about 50 or greater on theShore D Hardness scale for polymeric materials as described and measuredby the American Society for Testing and Materials (ASTM), headquarteredin Philadelphia, Pa. In one aspect, the combination of materials has ahardness of about 80 or greater on the Shore D Hardness scale forpolymeric materials. Additionally, the polishing article 205 generallyincludes a surface roughness of about 1 micron or less.

Alternatively, the polishing article 205 may comprise a metal meshdisposed in the conventional polishing material. The metal mesh maycomprise a chemically inert conductive material, such as platinum, whichhas a resistivity 9.81 μΩ-cm at 0° C. The metal mesh may also includematerials that have been observed to react with the surroundingelectrolyte, such as copper which has a resistivity of 1.6 μΩ-cm at 0°C., if the metal mesh is chemically insulated from the electrolyte suchas by a conformal layer of conventional material.

Further, the invention contemplates the use of abrasive materialsembedded in the conventional polishing material. In such an embodiment,the fixed abrasive particles generally include conductive abrasivematerials. The invention further contemplates other polishing articleconfigurations, such as polishing webs and linear polishing belts, inaddition to polishing pads.

While foregoing is directed to various embodiments of the invention,other and further embodiments of the invention may be devised withoutdeparting from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

1. An article of manufacture for polishing a substrate, comprising: aconductive material layer; a polishing material having a partiallyconductive polishing surface disposed on the conductive material layer,the partially conductive polishing surface adapted to contact thesubstrate; a plurality of perforations formed in the conductive materiallayer and the polishing material; and a plurality of grooves disposed inthe polishing material.
 2. The article of claim 1, wherein theconductive material layer comprises one or more conductive contacts forcoupling to a power source.
 3. The article of claim 1, wherein theconductive material layer comprises a metal film.
 4. The article ofclaim 1, further comprising: an electrode disposed below the conductivematerial layer, wherein the electrode is exposed to the partiallyconductive polishing surface by the plurality of perforations.
 5. Thearticle of claim 1, wherein the polishing material comprises aconductive material disposed in a polymer binder.
 6. The article ofclaim 5, wherein the conductive material comprises a conductive fillerselected from the group of carbon powder, carbon fibers, carbonnanotubes, carbon nanofoam, carbon aerogels, and combinations thereof,and the polymer binder comprises a dielectric material selected from thegroup of polyurethane, polycarbonate, polyphenylene sulfide, filledpolymers, foamed polymers, and combinations thereof.
 7. The article ofclaim 1, wherein the plurality of perforations define a perforationdensity between about 30 to about 80 percent of the surface area of thepolishing article.
 8. The article of claim 1, wherein the plurality ofperforations define a perforation density of about 50 percent of thesurface area of the polishing article.
 9. The article of claim 1,wherein the conductive surface has a resistivity of about 10 Ω-cm orless.
 10. An article of manufacture for polishing a substrate,comprising: a perforated dielectric support layer; a perforatedconductive material layer disposed on the perforated dielectric supportlayer; an electrode disposed below the dielectric support layer; and apolishing material disposed on the conductive material layer, thepolishing material having a partially conductive polishing surfaceadapted to contact the substrate and having a plurality of perforationsand a plurality of grooves formed therein, wherein the conductivematerial layer comprises one or more conductive contacts adapted tocouple to a power source.
 11. The article of claim 10, wherein theperforated conductive material layer comprises a metal film and thepolishing material comprises a conductive material disposed in a polymerbinder.
 12. The article of claim 10, wherein at least a portion of theplurality of grooves intersect with at least a portion of the pluralityof perforations.
 13. The article of claim 10, wherein the perforationsin the polishing material and the conductive material layer aresubstantially aligned with perforations in the dielectric support layer.14. The article of claim 10, wherein at least a portion of the pluralityof grooves of the polishing material intersect with at least a portionof a plurality of perforations disposed in the polishing material, theconductive material layer, and the dielectric support layer.
 15. Anarticle of manufacture for polishing a substrate, comprising: aconductive material layer; a polishing material having a partiallyconductive polishing surface disposed on the conductive material layer,the partially conductive polishing surface adapted to contact thesubstrate; an electrode disposed below the conductive material layer; aplurality of perforations formed in the conductive material layer andthe polishing material; and a plurality of grooves disposed in thepolishing material, wherein the electrode is exposed to the partiallyconductive polishing surface by the plurality of perforations formed inthe conductive material layer and the polishing material.
 16. Thearticle of claim 15, wherein the conductive material layer comprises oneor more conductive contacts for coupling to a power source.
 17. Thearticle of claim 15, wherein at least a portion of the plurality ofgrooves intersect with at least a portion of the plurality ofperforations.